Process for the synthesis of 4-methyl-17-alpha-hydroxyprogesterone and its esters



United States Patent PROCESS FOR TEE SYNTHESIS OF 4-ME'1HYL-17- ALPHA-HYDROXYPROGESTERONE AND ITS ESTERS Bruno Camerino, Milan, Umberto Valcavi, Varese,

Domenico Cattapan, Milan, and Bianca Pateili, Stradelia, ltaly, assignors to Societa Farmaceutici Italia, a corporation of Italy No Drawing. Filed Apr. 14, 195% Ser. No. 806,224

Claims priority, application Great Britain Apr. 16, 1958 8 Claims. (Cl. 260-23955) The present invention relates to 4-methyl-l7-alphahydroxyprogesterones and esters thereof, and a process for the synthesis of such compounds.

These new compounds have been found to display a progestative activity which is at least equal to that of progesterone when applied percutaneously and superior to that of 17-alpha-acetoXy-progesterone and 17-alphaethynyl-testosterone when applied per os.

The uinyention provides 4-methyl-17-alpha-hydroxyprogesterond'and-esters thereof having the general formula:

in which R represents a hydrogen atom or an acyl radical derived from an aliphatic carboxylic acid containing notmore than 9 carbon atoms. I

Particular compounds provided by the invention are 4-methyl-17-alpha-hydroxyprogesterone and 4-methyl-17- alpha-acetoxy-progesterone.

The compounds provided by the present invention may be prepared by a process illustrated by the following scheme:

I ketalization j I formation of an enamme Patented Feb. 26, 1963 "Ice iii

l l hydrolysis N (IV) 0 so I 0 :l

0 "OH hydrolysis dehydration O-- V) Thus, they may be prepared starting from 4,17-alpl1adihydroxyprogesterone-4-acetate (I) (which may be prepared by the method described in the specification of copending Camerino et al. application Serial No. 781,945, filed December 22, 1958, now U.S. Patent No. 3,030,390) I which is treated with an excess of ethylene glycol in 3, enzene at the boiling point in the presence 'of'p-tolueneulfonic acid to give the 20-mono-ethylene-ketal (II). it is surprising that the 3,20-bis-ethylene-ketal is not ormed but only the lo-rnono-ethylene-ketal.

The ketal (II) is then treated in the warm with pyrroliline in methanol and'the buteneimine is formed, hylrolysis of the acetic ester in position 4 taking place imultaneously to give 3-.(N-pyrrolidinyl) -delta-2-pregnent7-alpha-ol-4,20-dione-20-ethylene-ketal (III). The 3- yrrolidne derivative (III) reacts in two tautomeric 'orms (enolic and ketonic) as follows:

The B-pyrrolidone derivative (III) is then reacted with a Grignard reagent (CH MgI) and thebuteneimine (IV) is obtained. This, without pnrificationtis hydrolyzed in position 3 by boiling it with a butter solution consisting of acetic acid and potassium acetate to obtain 4-methylpregnant-4,17-alpha-diol-3,20-dione-20-ethylene-ketal (V). This compound (V) is treated with warm concentrated hydrochloric acid in methanol in order to selectively dehydrate the hydroxyl groupin position 4 without removing that in position 17 and simultaneously the 20-monoethylene-ketal is hydrolyzed to give 4-methyl-17-alphahydroxyprogesterone (VI).

The esters may. be obtained by esterification with the anhydride on chloride of an aliphatic carboxylic acid containing not more than 9 carbon atoms in the presence of p-toluene-sulfonic acid.

The following examples are given to illustrate the present invention.

EXAMPLE 1 4 ,1 7 -A lpha-D ihy dr0xypr0gester0ne-4 -A aerate-20- Ethylene-Ketal (H) 2.5 g- 4';1-7 alpha-dihydroxyprogesteronei-acetate are reacted in 75 cc. anhydrous benzene with 20 cc. ethylene glycol and 75 mg. p-toluene-sulfonic acid monohydrate: 75 cc. benzene are distilled ofi; 75 cc. benzene are added, the solution is refluxed for 5 hours, cooled, washed with water,.withan aqueous- 10% NaHCO solution and finah ly with water until. neutral, then it is driedvand evaporated under vacuum to dryness.

The residue iscrystallized from, methanol thus obtain.- ing' 1.2 g; 4,17-alpha dihydroxyprogesterone-4-acetat-20- ethylene-ketal having a melting point of 2l32l5 Q, 7=.13 ,400. The mother liquor is evaporated to'dryness and treated with cc. aqueous acetic acid solutionv for 20 minutes onawater bath; it is thenpoured into 200 cc. aqueous. 10% Na CO solution and filtered; after crystallizationirom aqueous methanol" 1.2 g'.-- starting product arerec'overedr I EXAMPLE 2 S-(N-Pyrolidinyl) -D elta-2-Pregnen-17-AlphaeOl-4,20-

Dione-ZO-Ethylene-Ketal (III) 1 .2, g. 4.,t7-alpha-dihydroxyprogesterone-4 acetate-20- ethylene-ketal' are dissolved in cc. warm methanol under nitrogen; 1.6 cc. pyrrolidine are added to the solution and the mixture is refluxed for 2 hours. A further 0.8 cc. pyrrolidine are then added and the whole is re- After cooling with an icefluxed again for 30 minutes. salt mixture the product is filtered; 6 5 0 mg of a product having a melting point of 215-220. C. are obtained. By concentration of the mother li'quora further 350 mg. 3-(N-py-rrolidinyl)-del-ta-2-pregnen lTl-alpha-ol-4,2O-

dione-ZO-ethylene-ketal, having a melting point of 212- 217" 0., are recovered.

EXAMPLE 3 4-Methyl-Pregnan-4,1 7-A lpha-Diol-iZO-Dione-ZO- Eihylene-Ketal (V) 7 1 hour, methanol is evaporated under vacuum and the solution is diluted with Water and filtered, thus obtaining 130 mg. of a product melting at 163-170 C. By recrystallization from methanol, 80 mg. 4-methyl-17-alphaacetoxyprogesterone, melting point 170174 C., E25o=- 5. 13,500, are obtained.

From the biological comparison between 4-methy1-17- alpha=acetoxyprogesterone and 17alpha-ethynyltestosterone the following results are obtained:

TABLE I Method of Prolifera- Sterold dose, administration degree .mg tion according to-McPhail l7-al ha-ethynyltestosteronen 5 per 05. 1.8 Do do 2.8 -rnethyl 17 alpha acetoxyproges- 1 do 2. 7

terone.

Do.. 0.5- do--...--- 1.8

TABLE II [Relative power of 4-methyl-l'i-alpha-acetoxyprogesterone in comparison with 17-a1pha-ethynyltestosterone, both per os] 17-alpha-ethynyltestosterone 1 4-methy1-'17-alpha-acetoxyprogesterone 10 TABLE III [Progestative activity of 4-methyl-1T-alpha-acetoxyprogesterone per os] [Relativ pow-u of 4-methyl-17-alpha-acetoxyprogesterone per es in comparison with that of progesterone by subcutaneous application] Progesterone 1 4-methyl-17-alpha-acetoxyprogesterone 0.61 17-alpha-acetoxyprogesterone 0.17

TABLE V [Relative power of 4-methy1-1'Z-alpha-acetoxyprogesterone in comparison with that of 17-alpha-acetoxyprogesterone, both per os] 17-alpha-acetoxyprogesterone 1 4-rnethyl-17-alpha-acetoxyprogesterone 3.5

The preparation of 4,17-alpha-dihydroxy-progesterone, and of the corresponding 4-acetate, is described in the copending. application of Camerino et 211., Serial No. 781,945, filed December 22, 1958, as follows:

24 cc. 4 N sodium hydroxide and 40 cc. 130-vol. hydrogen peroxide are added to 12 g. 17-alpha-acetoxyprogesterone dissolved in 1.6 liters methanol and cooled to 15 C. The whole is kept in a refrigerator at +5 C. for-1 hour.

264cc. glacial-acetic acid arethen added, the mixture is poured into 8 liters water and the precipitate, consisting of a mixture of- 4,5-beta-and-4,5-alpha-epoxy-17-alphaacetoxyprogesteronehaving a melting point of 193-202 C, is filtered. The ultraviolet spectra of-the product do not show any absorption at between 220 and 300 my, and elementary analysis gives the following results:

Found, percent: C, 71.12; H, 8.41. For C H O calculated, percent: C, 71.10; H, 8.31.

The chemical structure of the compound, which is-obtainedwith a yield of isdemonstrated by the fact that: itgives again the starting compound, 17-alphaacetoxyprogesterone, when heated with Kl for 10 minutes in acetic acid.

A solution of 6.7 cc. concentrated sulfuric acid in 28 cc. glacial aceticacid (pure for analysis) is added to 13.2 g. raw 4,5-epoxy-17-alpha-acetoxyprogesterone dissolved in 66 cc. glacial'acetic acid (pure for analysis). This mixture is left to stand overnight at room temperature and is then poured into 200 g. ice, while stirring and filtered While washing with Water until the filtrate is neutral.

12.5 g. of a product having a meltingpoint of 160172 C. are obtained. By recrystallization from diluted methanol the melting point rises to l97-200 C.; e =12,500; it gives a blue color with a FeCl solution.

Found, percent: C, 70.90; H, 8.54. For C d-1 0 calculated, percent: C, 71.10; H, 8.31.

A solution of 1 g. potassium carbonate in 16 cc. water is added to 1 g. 4-hydroxy-17-alpha-acetoxyprogesterone dissolved in 100 cc. methanol. The mixture is refluxed for 1 hour and then kept at room temperature; thereafter, it is diluted with water and filtered; 0.8 g. 4,17-alphadihydroxyprogesterone with a melting point of -170 C. is obtained, which after double crystallization from methanol, appears as crystals having a melting point of 229-231 C.; 6 is 11,800; it assumes a blue color when treated with-a FeC1 solution.

Found, percent: C,72.43; H, 8.95. For C l-1 0. calculated, percent: C, 72.80; H, 8.73.

3.2 g. 4,17-alpha-dihydroxy-progesterone, dissolved in 25 cc. pyridine, are acetylated with 3.5 cc. acetic anhydride. at room temperature for 20 hours. This mixture isthenpouredinto 100-g. ice-.andfilteredythe precipitate iszwashed with water until the filtrate is neutral.

3.4g. 4-acetoxy:17 alphaehydroxyrprogesterone, with ,a melting. point of. 1904195? C. are obtained. By'recrystal;

lization fromzdiluted'methanol .a product havinga mel i point of-198f C., e =.15,400,is ,obtained..

Found, percent: 0, 71.13;H, 8.45., For C H Q5, calculated, percent: C; 71.10; H,.8.30.v

As indicated above, theacylation of. the 4-hydroxy group by means of other esterifyingagents, such. as caproic anhydride, ,oenanthic, anhydride, and ,cyclQpcntylpropioniG anhydride, proceeds analogously to. the, preparati n-him? 4-acetate in Example 5 above. The therapeuticapplication of the; corresponding 4-esters,-,,andomerainuthe same manner as described for the. 4-acetate, is withinthescopeof this disclosure.

The term, aliphaticj? as used; herein, is inclusiveof cycloaliphatic.

We claim;

P cess-forrmak gr A-m hyhl.7 a pha acy qxyr p cgc t ronehav nc e; ollowing: general formu a:

where R is the radical of an aliphatic carboxylic acid containing not more than 9 carbonatoms, comprising sub-l jecting 4,17 alpha dihydroxyprogesterone-4-acetate to mono-ketalization, in the 20-position, by reaction with ethylene glycol in the presence of: para-toluene-sulfonic acid to obtain the corresponding mono-20-ethylene-ketal, treating the latter with pyrrolidine in warm methanol to make the 3-pyrrolidine derivative, subjecting the latter to a Grignards reaction with methyl magnesium iodide and then treating with potassium acetate in aqueous acetic acid to obtain 4-methylpregnan-4,17-alpha-diol-3,20 dione20- (112 P iii l i ofia 0 A Grignard reagent prepared from 5.5 g. Mg, 14.6 cc. CH I and 40 cc. anhydrous ether, is added to a solution of 1.25 g. 3-(N-pyrrolidinyl)-delta-2-pregnen-17-alpha-o1- 4,20-dione-ZO-ethylene-ketal in 160 cc. anhydrous benzene at room temperature While stirring. The mixture is refluxed for 6 hours and then kept at room temperature overnight; the product is decomposed by treatment with 60 cc. water, while cooling with an ice-salt mixture, and neutralized with an aqueous 50% CH COOH solution. The organic layer is separated, the mother liquor extracted times with 100 cc. benzene, the solvent is then treated with water, with an aqueous NaHCO solution again with water, and dried by evaporation under vacuum.

The solid residue Weighs 1.2 g.; a sample crystallized from methanol melts at 190-194" C. (transparent to U.V.).

4.7 cc. H O, 2.1 cc. CH COOH and 2.1 g. CH COOK are added to 1.2 g. of this product (i.e. 3-(N-pyrrolidinyl)- 4 methyl delta-2-pregnen-4,17-alpl1a-diol-20-one-20- ethylene-ketal) dissolved in 25 cc. methanol. The mixture is refluxed for 3 hours, concentrated under vacuum to a small volume, and diluted with Water; by filtration, 1.1 g. 4-methyl-pregnan-4,17-alpha-diol-3,20-dione-20- ethylene-ketal having a melting point of 191-196 C. (transparent to UN.) are recovered.

OH: OH

g. 4-methyl-pregnan-4,l7-alpha-diol-3,20-dione-20-ethy1- ene-ketal dissolved in 75 cc. methanol; the mixture is refluxed for 3 hours and then concentrated under vacuum to a very small volume; it is then washed again with water and filtered; after crystallization from methanol mg. 4-methyl-17-alpha-hydrcxy-progestcrone having a melting point of 224232 C. are obtained. A sample recrystallized melts at 238240 C; 6 14,000.

I EXAMPLE 5 4 -M ethyl-1 7-A lph a-Acetoxyprogesterone (VII) Ow E 0.32 g. 4-methyl-17-alpha-bydroxyprogesterone having a melting point of 224-232 C. are treated with 3 cc. acetic anhydride and 10 mg. of p-toluene-sulfonic acid monohydrate at 90 C. for 30 minutes; the mixture is kept at room temperature for 3 hours, thus obtaining a crystalline precipitate which is filtered and washed first with 1 cc. acetic anhydride and then with Warm water. 250 mg. of a product melting at 235-246 C., e 19,000 are obtained as white flakes.

0.58 cc. concentrated sulfuric acid and 1.15 cc. water are added to mg. of this product (i.e. 4-methyl-delta- 2,4-pregnadiene-3-beta,l7-alph-a-diol 20 one-3,17-diacetate) dissolved in 90 cc. methanol. After refluxing for mono-ethylene-ketal, dehydrating the latter with concentrated hydrochloric acid in methanol, thereby also saponifying the ketal linkage in the 20 position, to obtain 4 methyl-17-alpha-hydroxyprogesterone, esterifying the latter by treating with an agent of the group consisting of the anhydride and chloride of an aliphatic acid having not more than 9 carbon atoms, to obtain a 4-methyl-17-alphaacyloxy-progesterone.

2. A process for making 4-methyl-l7-alpha-hydroxyprogesterone comprising subjecting 4,17-alpha-dihydroxyprogesteroner-acetate to mono-ketalization, in the 20- position, by reaction with ethylene glycol in the presence of para-toluene-sulfonic acid to obtain the corresponding mono-ZO-ethylene-ketal, treating the latter With pyrrolidine in Warm methanol to make the S-pyrrolidine derivative, subjecting the latter to a Grignards reaction With methyl magnesium iodide and then treating with potassium acetate in aqueous acetic acid to obtain 4-methylpregnan-4,17- alpha-diol-3,20-dione-Ztl-mono-ethyiene-ketal, dehydrating the latter With concentrated hydrochloric acid in methanol, thereby also saponifying the ketal linkage in the 20 position, to obtain 4-methyl-17-alpha-hydroxyprogesterone.

3. A process comprising subjecting 4-methylpregnan-4, 17 alpr a-diol-3,20-dione-mono-2()-ethylene-ketal to dehydration and saponification by refluxing a mixture there of with concentrated hydrochloric acid in methanol, to obtain 4-methyl l-7-alpha-hydroxyprogesterone.

4. A process comprising subjecting 4-methylpregnan-4, 17- alpha-diol-3,ZO-dione-mono-ZO-ethylene-ketal to dehydration and saponification by refluxing a mixture thereof With concentrated hydrochloric acid in methanol, to obtain 4-methyl-l7-alpha-hydroxyprogesterone, and esteritying the latter by treating with an agent of the group consisting of the anhydride and chloride of an aliphatic acid having not more than nine carbon atoms, to obtain the corresponding 4-methyl-17-alpha-acyloxy-progesterone.

5. A process comprising subjecting 4,17-alpha-hydroxyprogesteronet-acetate to mono-ketalization by treating it with ethylene glycol in the presence of para-toluene sulfonic acid, to obtain the corresponding mono-ZO-ethylene-ketal.

6. A process comprising subjecting 4,17 -alpha-hydroxyprogesterone-4-acetate to mono-ketalization by treating it with ethylene glycol and p-toluene-sulfonic acid in anhydrous benzene, distilling otf benzene, adding benzene and refluxing, washing with dilute aqueous alkali, and re covering the corresponding mono-ZO-ethylene-ketal.

7. A process'of making a mono-ketal, the 4-methylpregnan 4,17 alpha diol 3,20-dione-20-ethylene-ketal, comprising refluxing a mixture of 4,17-alpha-hydroxyprogesterone-4-acetate with ethylene glycol and p-toluene sulfonic acid in an organic diluent inert in the reaction.

8. A process of making 4-methyl-l7-alpha-hydroxyprogesterone comprising treating 4,17-alpha-dihydroxyprogesterone-4-acetate-ZO-ethylene-ketal with pyrrolidine in Warm methanol to make the 3-pyrrolidine derivative, subjecting the latter to a Grignards reaction with methyl magnesium iodide and then treating with potassium acetate in aqueous acetic acid to obtain 4-methyl-pregnan- 4,17 alpha di0l-3,20-dione-20-mono-ethylene-ketal, dehydrating the latter With concentrated hydrochloric acid in methanol, thereby also saponifying the ketal linkage in the 20-position, to obtain 4-methy1-l7-alpha-hydroxyprogesterone.

Great Britain Oct. 5, 1955 Great Britain Nov. 9, 1955 

1. A PROCESS FOR MAKING A 4-METHYL-17-ALPHA-ACYLOXYPROGESTERONE HAVING THE FOLLOWING GENERAL FORMULA: 